Big Eye on the Sky by Neil English

What the James Webb Space Telescope May Reveal about our Universe

After decades of planning, major budgetary setbacks and innumerable launch delays, the greatly anticipated successor to the Hubble Space Telescope (HST) finally blasted off on a giant Ariane 5 rocket from Kourou, French Guiana, on Christmas Day 2021 to begin its perilous million-mile journey to its destination beyond the earth’s orbit. Called the James Webb Space Telescope (JWST) in honor of the pioneering NASA administrator James Webb, under whose aegis the Mercury, Gemini and early Apollo space missions proved highly successful, this $10 billion giant infrared telescope dwarfs anything previously deployed into the vacuum of space, and over the next two decades promises to revolutionize our understanding of the cosmos and our place within it.

In the nerve-wracking weeks after its launch, JWST reached and settled into its ultra-stable orbit, some 930,000 miles beyond the orbit of the Earth, and began to unfold its eighteen hexagonal gold-plated mirrors. Here at what’s called the Lagrangian point 2 (L2), where the gravitational forces due to the Sun and the Earth are roughly equal, the orbiting space observatory is constantly hidden from the burning rays of the Sun, and its enormous heat shield further protects it from additional heat from the Earth and our Moon. Because the telescope “sees” in the infrared region of the spectrum, it detects even tiny sources of thermal energy. And while our planet and moon don’t seem to be giving off much in the way of heat to our eyes, they are positively glowing in the infrared, and so must be always blocked off from the telescope mirrors as it peers out into the Universe. Cooled to a temperature just 50 degrees above absolute zero (-370^o Fahrenheit), JWST is expected to yield spectacular images of mysterious celestial objects, both from within our galaxy and from far beyond.

Unlike conventional visible light telescopes such as HST, the JWST uses about five wedding rings’ worth of gold to plate the mirror surfaces. Because gold reflects up to 99 per cent of the infrared radiation incident upon it (higher than silver or aluminum) and has great chemical inertness, it was commissioned as the reflective surface of choice to focus infrared radiation. That’s the region of the spectrum we feel as heat. So, in a way, JWST is a night vision scope on steroids! The honeycomb arrangement of mirrors, which collect about 6.5 times more light than the HST, was unfurled into an ultra-precise geometry, with actuators helping to align all the optical components with a precision equivalent to one ten thousandth the width of a human hair. Another milestone was reached on March 16, 2022, when optical engineers conducted a highly complex task called fine phasing, where all eighteen mirrors were optimally aligned to create a perfect image of a test star. If all goes well, JWST will begin taking pictures of the infrared Universe in late spring or early summer 2022. Here’s a neat YouTube presentation of how JWST unfolded after arriving at its orbital destination.

Mission Goals

Unsurprisingly, a telescope as powerful and technologically sophisticated as JWST will be primarily assigned to questions of cosmogony, that is, origin science. When did the first galaxies form? What did they look like? How and when did the first stars form? How are planetary systems forged? What are the physical characteristics of the planets that form around neonatal stars, and are any of these planets capable of hosting life? Observations of the earliest galaxies will help cosmologists refine the Big Bang model and provide new insights into the earliest and most elusive epochs in cosmic history.

It's widely anticipated that JWST may provide our first glimpses of the first stars in the Universe, which are predicted to be more massive and short-lived than later stellar generations. In particular, one key test for Big Bang cosmology is the identification of so-called Population III stars, which were forged only from the primordial elements created just a few hundred thousand years after the explosive beginning of our Universe. All known stars have been enriched with various amounts of heavier elements forged from later generations of stars, but finding stars made up of only those elements produced in a hot Big Bang model – hydrogen, helium, and lithium – would do much to bolster our confidence in the theory. Furthermore, because JWST is tuned to the near- and mid-infrared regions of the spectrum, it will be able to peer far more deeply inside huge clouds of gas and dust – the nurseries of stars – to get exquisite details of how these clouds collapse under gravity to forge new stars. These studies will refine details of how stars are born and evolve over time.

Closer to home, JWST will also be employed to conduct specialized studies on a wide range of solar system objects, such as the outer planets and their moons, comets, asteroids, Kuiper Belt Objects, and dwarf planets. Doubtless, our solar system is still rich in mystery, and JWST will enable us to see our neighbors in space in new and spectacular ways!

Needle in a Haystack

Perhaps the most exciting prospect for scientists is finding planets that are potentially habitable. This is an important question for humanity in general but also for Christians. JWST will be capable of detecting much smaller planets than can currently be detected owing to its much greater light gathering power and resolution than any other space telescope. By watching planets as they transit the face of their host stars, JWST will be able to measure the size and likely mass of these worlds to much higher precision than can currently be achieved. But JWST will also be capable of sampling the atmospheres of these alien worlds, sniffing-out gases that scientists associate with life on earth. For example, a planet having high levels of molecular oxygen and water vapor would be a very exciting find indeed, but how likely are we to find such a world?

According to the astrophysicist and committed Christian, Bijan Nemati, a Principal Research Scientist at the University of Alabama in Huntsville, from what we have so far learned about extrasolar planets (those worlds orbiting stars different from the Sun), it’s going to be much more difficult than finding a proverbial a needle in a haystack:

Back in the 1960s, astronomers were optimistic that a few million Earth-like planets must surely exist in our galaxy, but fast forward a half century or more and what we find is that the conditions necessary for life are far more fine-tuned than we anticipated at the beginning of the space age.

Nemati argues from probability:

Suppose there are just twenty parameters that need to be met to make earth habitable. Let’s suppose we generously assign a probability of 10 percent that each of those requirements be met, then the chances are less than a millionth of a trillionth. That makes the earth or an earth-like planet exceedingly rare.Another way of looking at it is that you’d have to search out tens of thousands of Milky Ways before you’d expect to find a single planet that meets all these requirements.

Dr Nemati, who worked on the JWST in his earlier career, is currently developing instrumentation expected to go on board the soon-to-be- launched Nancy Grace Roman Space Telescope, designed to unravel some of the mysteries of dark matter and dark energy, the cutting edge of astrophysical research, but also to study exoplanet physics and chemistry in greater detail than JWST.

Though Dr Nemati is probably being realistic about the prospects of ever finding another world like ours, it may still come as a surprise, or even a disappointment, to some. But if we are creatures made in the image of God, is it not reasonable to think that there’s something very special about our existence? Are we not fearfully and wonderfully made, as the Psalmist declares?

Whatever it finds – expected or unexpected - JWST will be probing the deep things of God. After all, wisdom is older than nature, and all truth is God’s truth. Did the Universe have a beginning? Why does it have so many stars and planets? Is life peculiar to the earth, or is it widespread in the Universe? From where did we come? And to what degree did the cosmos ‘know’ we were coming?

Golly gosh, we do live in exciting times!

Dr. Neil English’s book, Chronicling the Golden Age of Astronomy, celebrates four centuries of telescopic astronomy and the characters who shaped the science.